A popular type of hand cleaner, used especially in factories, garages and other industrial and commercial establishments, is of a viscosity much like that of a pasty creme, too great to flow downward under the force of gravity. Dispensing such a material involves problems different from those of dispensing a flowable liquid. Loading and reloading of such dispensers has offered serious problems, particularly with regard to the channeling of air through the material on dispensing and the elimination of air in refilling dispensers.
Such hand cleaner material may be furnished in cylindrical cans; and these may be left in place over a cylindrical reservoir for the material, as shown in U.S. Pat. Nos. 2,818,998 to Jones and 3,809,293 to the present inventor. In the types of dispenser there shown, when the reservoir is partly filled an additional can of material may be so put in place over it, to descend as the material within the reservoir is pumped from it; this descent is caused by outside air pressure, acting against the vacuum induced by the dispensing action. In both of these patents the problem of charging a partially-filled dispenser and eliminating the air between the material already in the reservoir and the new material to be added is met by providing a vertical pipe within the reservoir, closed at its top end and having a series of orifices at its sides so that the intervening air, at any level, may be forced into the pipe and discharged downward during the filling operation. Of these patents, U.S. Pat. No. 3,802,293 shows that the viscous material may be drawn out by being pumped in a downward course leading from the bottom of the reservoir through a ball valve and thence pressed by a piston through a second ball valve to a discharge outlet.